Whe you write “You have no idea…” yes, many of us have an idea 
Has he tried beta blockers? That was not addressed in your response.
Seeing a lawyer does NOT mean making a big legal thing out of it. I spent $200 finally on a lawyer, met with her (only once), received some elegant solutions which I could then cite when talking with the school. Mentioning that I got the suggestions from a lawyer (with a smile) really got things rolling. I don’t think any of us are thinking about you filing a complaint or seeing them in court. Legal advice from someone familiar with the ADA as it is honored at the college level can really be very helpful (as can OCR, where we also got advice but certainly did not file a complaint).
We understand you have been dealing with this for years and are a great parent who has researched and gone to the ends of the earth.